We propose to develop a dual-mode, optical-EEG sensing system that provides for 4D functional imaging in freely moving animals. The proposed system employs a tethered arrangement that attaches to a two-stage detachable measuring head with one end surgically fixed to the head of a rat. This allows for concurrent collection of whole brain time-series DOT and multilead electrophysiological data while permitting the animal to engage in complex behaviors. Planned are a systematic computational, laboratory and animal studies that will serve to define the limits of performance and fidelity of data quality under realistic conditions. Preliminary data obtained shows that whole head hemodynamic responses gated to behavior dependent hippocampal activation states are spatially distinct and reproducible. The proposed system offers a unique opportunity to explore the dependence of a wide range of complex behaviors on underlying neural and neuro-vascular coupling events and should prove of significant value to the basic neuroscience and pharmaceutical communities. [unreadable] [unreadable] [unreadable]